The present invention relates to a helical blade type compressor used as a compressor for composing a refrigeration cycle of, for example, an air conditioner.
The helical blade type compressor has been recently proposed.
In this helical blade type compressor, a cylinder for composing the compression mechanism is disposed in an enclosed case, and a roller revolves in the cylinder. Spiral grooves are provided in the roller circumference or cylinder inside, and helical blades are contained to be free to move in and out.
In such constitution, plural combustion chambers are formed continuously between the cylinder and roller, and between mutual helical blades. When the roller revolves in this state, the refrigerant gas is sucked into the compression chamber at one end side, and is compressed as being gradually transferred to the compression chamber at other end side.
According to this kind of compressor, defective sealing performance in the conventional reciprocating type or rotary type compressor can be eliminated, and the sealing performance is enhanced in a relatively simple constitution, and efficient compression is realized, while it is easier to manufacture and assemble parts.
In this helical blade type compressor, sealing between the high pressure side and low pressure side is achieved by the sliding surface or tiny gap between the roller and the bearing member which receives the thrust load of the roller.
However, in the structure of sealing by making use of the thrust load of the roller, it is hard to keep a sufficient sealing performance, and the thrust sliding surface may be seized in case of occurrence of an excessive thrust load. In the conventional structure, since the thrust load acting on the roller cannot be controlled easily, there were problems to be solved in relation to performance and reliability.